1. Field of the Invention
The present invention relates to an automatic transmission for automobiles using a torque converter and planetary gear train.
The automatic transmission using the torque converter and a plurality of rows of planetary gearsets provides different gear ratios by selectively engaging the planetary gearsets by friction elements.
2. Description of the Prior Art
To achieve the formation of the gearshift positions to ensure smooth gearshift in an automatic transmission with multi-step gearshift positions, it is desired to use many friction elements. Of the friction elements, a clutch in particular is generally of such a construction that a clutch hub, friction plates, separate plates and a hydraulic piston as a servo device are housed within a rotatable drum. The provision of a number of clutches, therefore, requires space wide enough in the axial and diametral directions for the arrangement of the clutches. And besides, there will arise such a problem that it is difficult to provide a sufficient space for mounting a supporting device for supporting the rotating clutch drum.